If it's not what You are looking for type in the equation solver your own equation and let us solve it.
D( x )
(3*x)^2 = 0
(3*x)^2 = 0
(3*x)^2 = 0
9*x^2 = 0 // : 9
x^2 = 0
x = 0
x in (-oo:0) U (0:+oo)
Y = pi/((3*x)^2) // - pi/((3*x)^2)
Y-(pi/((3*x)^2)) = 0
(-(pi/9))*x^-2 = -Y // : -(pi/9)
x^-2 = Y/(pi/9)
-2 < 0
1/(x^2) = Y/(pi/9) // * x^2
1 = (Y/(pi/9))*x^2 // : Y/(pi/9)
1/(Y/(pi/9)) = x^2
x^2 = 1/(Y/(pi/9)) // ^ 1/2
abs(x) = 1/((Y^(1/2))/((pi^(1/2))/3))
x = 1/((Y^(1/2))/((pi^(1/2))/3)) or x = -(1/((Y^(1/2))/((pi^(1/2))/3)))
x in { 1/((Y^(1/2))/((pi^(1/2))/3)), -(1/((Y^(1/2))/((pi^(1/2))/3))) }
| 80g*1/2t=r | | 13m=-23+62 | | 80g*1/2t | | 3xp= | | x-logx=0.30 | | 3(3x-4)=6(2x-6) | | 7x+8x+2=18x-27-8 | | x+x+4x+4x=140 | | 4(w-2)=5(w-4) | | 9.7+x=0.6 | | 2.25+x^2-3x=-0.083 | | X-0.25x=840 | | cosine(5x)=0 | | 35=9+12+c | | (x^2-z^2)(x^2+z^2)= | | 2y=sqrt(9-9*y) | | sqrt(1+x^2)=0 | | 46s+16=10s | | sqrt(-3x+43)=x-5 | | 22=11(x-1) | | 3=3-y | | 1=3-y | | 3y^2-10y-16=0 | | 7/4(B)=7 | | y=5x^2+4x-6 | | 3a^4+2a^2-96=0 | | 6[7-(-2x-7)]=187x+159 | | x^2+y^2+6x+4y-51=0 | | 5(v-6)-4=5v-34 | | lnx+ln(x+2)=ln(2x+3) | | 3.7x+2.4y+6=0 | | (5x+6)(5x^3-4x^2+8x-5)= |